The present compound is a ferroelectric one having high speed of response to electric fields and is useful as a material for an electric indicative element of liquid crystal.
A large number of compounds have been proposed, for example, ##STR3## (Japan Kokai No. 61-271252), and ##STR4## (wherein R.sub.1 is a C.sub.6-18 alkyl group; X and Y are respectively hydrogen atom, halogen atom or a methyl group) (Japan Kokai No. 61-251639).
One requirement for this sort of compound useful as an electric indicative element is that a compound is able to transit to liquid crystal phase at a temperature near room temperature and that it is photochemically and chemically stable.